The interconnection of integrated circuit devices has traditionally been accomplished using wired technology, such as printed circuit and multi-wire boards. These technologies require a wired link embedded in or on a board or substrate that physically supports a plurality of IC devices and other components. The wired link may be comprised of an etched conductive trace or conventional wire embedded in the circuit board. An electrical connection between a terminal on the IC device and a via or pad connected to the wire trace facilitates the transmission of a signal from one device to another. While such interconnections are commonly employed method for interconnecting IC devices, they incur a number of problems that impact the cost and performance of the IC devices.
The wire traces and associated solder joints of both cited technologies are costly to manufacture and are susceptible to failure both during and after manufacturing. In addition, when wire traces are of a relatively long length, they generate cross-talk between signals and cause additional signal loss due to signal reflections and the resistance of the wire trace itself. This limits the attainable bandwidth of the interconnecting signals and, thus, the bandwidth of the IC devices themselves. In addition, the traces and terminal connections also consume space on the board or substrate that could otherwise be utilized for supporting a larger number of IC devices or eliminated to create smaller products. The interconnection of a relatively small number of IC devices may require hundreds or thousands of interconnections on a single board or substrate. This often requires complex routing, resulting in increased engineering and manufacturing costs.
In a similar manner, the interconnection of IC devices located on different boards or substrates within a single enclosure has traditionally been accomplished via wires, electrical cables, back-planes, fiber optic cables or a combination of the foregoing. Wires, electrical cables and back-planes are susceptible to the same signal loss, space requirements, routing and cost problems associated with the wire traces of a single board or substrate. This is compounded, however, by the greater distances encountered between IC devices on different boards or substrates and the usual need for additional interconnection components required to connect the cable or back-plane to a wired link. While fiber optic links between boards or substrates eliminate some of the signal loss and cross-talk problems associated with electrical cables, they have similar space and routing requirements and are typically more expensive than electrical interconnect solutions.
The wired technologies cited above are also utilized for system-level communications, i.e., between self-contained devices, such as computers, peripherals, network routers, Original Equipment Manufacturer (OEM) products and sub-assemblies. In addition, wireless technologies, such as the IEEE 802.11 standard for wireless local area networks or the Bluetooth standard, are commonly used for communication among these types of system-level devices. See, for example, “Information Technology: Telecommunications and Information Exchange Between Systems—Local and Metropolitan Area Networks—Specific Requirements,” ANSI/IEEE Standard 802.11 (1999), incorporated by reference herein. Wireless links, however, have been traditionally restricted to this system-level domain due to their high cost and relatively low bandwidth compared to wired solutions. The conventional view has been that wireless links are too slow and expensive to compete with wired solutions for relatively short distances. In view of the foregoing, a need exists for a method and apparatus for interconnecting IC devices located on one or more boards or substrates within a single enclosure that overcome the problems and limitations of the prior art.